Structural characterization of AlN and AlGaN layers grown on GaN/AlN/Si 111 by plasma-assisted MBE

Abstract

Aluminum nitride (AlN) and high aluminum (Al) content aluminum gallium nitride (AlGaN) thin films were successfully grown on gallium nitride (GaN) layer by plasma-assisted molecular beam epitaxy (PA-MBE) system. The films were deposited on Si 111 substrate. A systematic study and optimization of the growth conditions was performed in order to grow AlN and AlGaN layers on GaN films. Epitaxial growth of GaN has been demonstrated to be feasible for substrate temperature (800°C and 850°C) which depends on a Ga/nitrogen flux ratio. The absence of cubic phase GaN buffer layer for both samples has shown that this layer possessed hexagonal structure. The AlN sample has a good optical quality as measured by the photoluminescence (PL) system.